Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link

Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.

Volume 32, Number 6—June 2026

Research

In Vitro Antifungal Drug Susceptibility of Feline Sporothrix schenckii Complex Isolates, Thailand, 2023–2025

On This Page
Materials and Methods
Results
Discussion
Suggested Citation
Tables
Table 1
Table 2
Table 3
Table 4
Downloads
RIS [TXT - 2 KB]
Article Metrics
Metric Details
Related Articles
T. indotineae Dermatophytosis, Singapore, 2025
Genomic Epidemiologic Description of C. auris
Detection of Coccidioides spp. Fungi Using ddPCR
More articles on Fungal
Author affiliation: Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand

Suggested citation for this article

Abstract

Feline sporotrichosis is a public health concern because it is a zoonotic illness and has a prolonged treatment time. We report laboratory-confirmed cases of feline Sporothrix schenckii complex infection submitted to a laboratory in Thailand during 2023–2025 and evaluate their in vitro antifungal drug susceptibility profiles for amphotericin B, itraconazole, posaconazole, voriconazole, ketoconazole, fluconazole, and flucytosine. A total of 1,178 S. schenckii complex isolates were identified. Overall, 368 isolates did not show reduced susceptibility. We observed single-drug reduced susceptibility to amphotericin B (60 isolates), posaconazole (41 isolates), voriconazole (9 isolates), and terbinafine (4 isolates). We observed a reduced susceptibility to itraconazole in 687 isolates: 321 single-drug, 270 co-reduced, and 96 multidrug-reduced isolates. An increasing number of feline sporotrichosis cases and escalating reduced susceptibility to itraconazole underscore the need for continued surveillance and susceptibility testing to support management in complex cases.

Sporothrix schenckii complex is a group of genetically related fungi within the genus Sporothrix, which includes S. schenckii sensu stricto, S. brasiliensis, S. globosa, S. mexicana, S. luriei, and S. albicans (1). S. schenckii are thermal dimorphic pathogens that live and grow in mold form in the environment (1,2). Humans and animals become infected through the implantation of spores from contaminated materials into subcutaneous tissue through cuts and scratches; the fungus then converts to yeast form within the host tissue (2). S. schenckii complex causes sporotrichosis in humans and animals; cats are the most susceptible species. The geographic distribution, pathogenicity, clinical manifestations, virulence, and antifungal drug susceptibility differ among species. S. brasiliensis is the most virulent and highly prevalent, causing animal sporotrichosis and zoonotic infections in Brazil and other South American countries. S. globosa is an emerging human pathogen in China and India, and human infection occurs through environmental transmission (3–5). S. schenckii s.s. has occasionally been reported as causing environmentally acquired infection globally. However, a specific clade of S. schenckii s.s. has recently emerged among cats in Thailand, and reports of cat-to-cat and cat-to-human transmission are increasing (6–8). Cats with sporotrichosis exhibit multiple ulcerative mucosal and cutaneous lesions. Infected cats can shed infectious yeast organisms through saliva, nasal secretions, wound exudates, and scratches or bites to humans, cats, and other species (9). Cats serve as a major reservoir and highly efficient transmitter of sporotrichosis (9,10).

The effective treatment of infected cats with antifungal drugs is essential for controlling feline sporotrichosis. Performing antifungal drug susceptibility testing and analyzing the MIC values of endemic strains are necessary for monitoring antifungal drug susceptibility patterns. Clinical decisions are typically made on the basis of established clinical breakpoints; however, the clinical breakpoints for Sporothrix spp. are currently unavailable (11). Therefore, characterizing wild-type (WT) or non–wild-type (non-WT) isolates on the basis of the epidemiologic cutoff values (ECVs) is useful for surveillance of emerging antifungal drugs resistance (12). WT isolates have no resistance mechanisms and typically exhibit expected antifungal drugs susceptibility profiles, whereas non-WT strains have shown evidence of acquired or mutational changes, which reduce their susceptibility to antifungal drugs and are associated with higher MICs. Sporotrichosis treatment requires the use of antifungal drugs for several months, which might lead to antifungal drug resistance in clinical cases. Itraconazole is the antifungal drug of choice and the first-line treatment for sporotrichosis (13,14). Other antifungal drugs, including azoles (i.e., fluconazole, ketoconazole, posaconazole, and voriconazole), polyene (i.e., amphotericin B), pyrimidine analog (i.e., flucytosine), and allylamine (i.e., terbinafine), have also been used as combination therapies for human and feline sporotrichosis and other dimorphic fungal infections to shorten the treatment duration and improve clinical outcomes (13,15–17). Data on antifungal drug susceptibility from feline S. schenckii s.s. isolates in Thailand (2018–2021) reported in 2022 and 2023 (6,18) showed that prolonged treatment and frequent combination therapy might alter susceptibility patterns and lead to more complex resistance. We report laboratory-confirmed cases of feline sporotrichosis in Thailand from 2023–2025; characterize the in vitro antifungal drugs susceptibility profiles of S. schenckii complex isolates from cats in Thailand to amphotericin B, itraconazole, posaconazole, voriconazole, terbinafine, ketoconazole, fluconazole, and flucytosine; define the WT population of those isolates from 2023–2025; and determine the cross-reduced susceptibility patterns of itraconazole and other antifungal drugs.

Materials and Methods

Fungal Isolates and Data Collection

All the sample collection and handling procedures were approved by the Institutional Animal Care and Use Committee at Kasetsart University (approval no. ACKU68-VET-085). Clinical samples from cats suspected of feline sporotrichosis, submitted during 2023–2025 from veterinary clinics nationwide to the Department of Microbiology and Immunology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, were included.

We inoculated wound swab samples collected from cats with ulcerated cutaneous lesions in Sabouraud dextrose agar (SDA) at 30°C and brain–heart infusion agar containing gentamicin (50 mg/L; General Drugs House, https://generaldrugshouse.com) at 35°C for 5–14 days. We identified the causative agent as S. schenckii complex on the basis of its thermal dimorphic characteristics: a yeast form on brain–heart infusion agar at 35°C and a mold form as a hyaline septate fungus with a flower-like arrangement of the rosette and sessile conidia on SDA at 30°C. We subcultured and stored the isolates in sterile water for further antifungal drug susceptibility testing. For each cat, we extracted from the database the age, sex, breed, body weight, and retrovirus-infected status (feline leukemia virus [FeLV] and feline immunodeficiency virus [FIV]) .

Antifungal Drug Susceptibility Testing

We tested the S. schenckii complex isolates for their susceptibility to 8 antifungal drugs: amphotericin B, itraconazole, posaconazole, voriconazole, ketoconazole, terbinafine, fluconazole, and flucytosine. We performed antifungal drug susceptibility testing by using the broth microdilution method (BMD) according to Clinical and Laboratory Standards Institute (CLSI) for filamentous fungi guidelines (CLSI M38-A3) (19,20). The final concentrations of all the drugs assigned for testing were 0.06–32 μg/mL for amphotericin B, itraconazole, and posaconazole; 0.12–64 μg/mL for voriconazole; 0.015–8 μg/mL for terbinafine and ketoconazole; and 0.5–256 μg/mL for fluconazole and flucytosine. We sourced the antifungal drugs from MilliporeSigma (Sigma Aldrich, https://www.sigmaaldrich.com). We performed antifungal drug susceptibility testing against the mold form of the S. schenckii complex isolates as described previously (6). We dissolved the antifungal drugs according to CLSI M38-A3 (20) and diluted in Roswell Park Memorial Institute 1640 medium (Invitrogen, https://www.invitrogen.com) buffered to a pH of 7.0 with 0.65 M of 3-(N-morpholino)-propanesulfonic acid (MOPS) buffer (Millipore Sigma) with L-glutamine and without bicarbonate to achieve 2× the final concentration of each drug. We then loaded the solution into 96-well U-shaped microplates. We harvested a conidia suspension from the 3-day-old cultures growing on SDA at 30°C and adjusted the cell density to an absorbance of 0.09–0.11 at 530 nm and diluted at 1:50 in an RPMI 1640 culture medium to obtain the final cell concentration necessary for testing. We incubated the inoculated microplate at 35°C for 72 hours and determined the MIC visually. We included Candida parapsilosis ATCC 22019 to verify the accuracy of antifungal drug concentrations and potency in BMD plates but not as a quality control strain for filamentous fungi susceptibility testing.

Antifungal Drug Susceptibility Analysis and Interpretation

To enable the parallel evaluation of the ECVs with those previously reported (21), we analyzed the MIC values of the isolates from Thailand. We calculated the MICs required to inhibit 50% (MIC50), 90% (MIC90), 95% (MIC95), 97.5% (MIC97.5), and 99% (MIC99) of the tested isolates. In addition, we determined the statistic mode by the highest frequency of MIC value for each antifungal drug. We identified the non-WT isolates as S. schenckii isolates with MIC values higher than the ECVs previously reported for amphotericin B (4 μg/mL), itraconazole (2 μg/mL), posaconazole (2 μg/mL), and voriconazole (64 μg/mL). The ECV for terbinafine has not yet been established; therefore, we defined a study-specific cutoff for terbinafine by statistical cutoff value at MIC97.5, according to CLSI M57 guidelines (22).

We used JMP Pro version 10 (SAS Institute, https://www.sas.com), GraphPad Prism version 9.0 (GraphPad, https://www.graphpad.com), and Stata version 14.2 (StataCorp, LLC, https://www.stata.com) for statistical analyses. We used Fisher exact test to assess the associations between the retroviral infections and non-WT populations. We also determined the associations between the non-WT isolates among the antifungal drugs. We considered results statistically significant when p<0.05.

Results

We identified 1,178 S. schenckii complex isolates over the 3-year sampling period. Of those, in 2023 we recovered 225 isolates, in 2024 we recovered 383 isolates, and in 2025 we recovered 570 isolates. The demographic characteristics of cats with S. schenckii complex (Table 1) included mean +SD age of 4.0 +3.3 years and mean +SD bodyweight of 3.83 +1.3 kg. Most of the cats were male (60.7%) and domestic shorthairs (91.6%). Retroviral testing was performed on 253 cats, of which 28.1% were positive for FeLV or FIV.

We determined the MIC50​, MIC90, MIC95​, MIC97.5​, MIC99​, and mode MIC values for all tested antifungal drugs (Table 2). Amphotericin B demonstrated MIC values ranging from 4 μg/mL (MIC50) to 16 μg/mL (MIC99​). Itraconazole and posaconazole exhibited high MIC values, with MIC50 values of 8 μg/mL (itraconazole) and 1 μg/mL (posaconazole), and MIC90​–MIC99​ exceeding 32 μg/mL. Voriconazole exhibited MIC values from 32 μg/mL (MIC50) to >64 μg/mL (MIC99​), whereas the MIC values for terbinafine ranged from 1 μg/mL (MIC50​) to 8 μg/mL (MIC99​). The MIC values were between 0.5–4 μg/mL for ketoconazole. Fluconazole and flucytosine had consistently high MIC values, with MIC50 ​to MIC99​ >64 μg/mL. The study-specific cutoff for terbinafine was assigned as 4 μg/mL according to MIC97.5.

We observed a predominance of WT isolate susceptibility toward amphotericin B (79.0%), posaconazole (73.9%), voriconazole (97.3%), and terbinafine (98.2%). In contrast, itraconazole revealed a predominance of non-WT isolate susceptibility (58.3%). The distribution of MIC values for amphotericin B, itraconazole, posaconazole, voriconazole, and terbinafine and MICs for antifungal drugs that do not have designated ECVs for S. schenckii complex are provided (Table 3).

We did not find an association between retroviral infections and non-WT isolates for amphotericin B (p = 0.2367), itraconazole (p = 0.2569), posaconazole (p = 0.2367), voriconazole (p>0.9999), and terbinafine (p>0.9999). We did observe significant associations between retroviral infections and non-WT isolates for itraconazole and those for amphotericin B (p<0.0001), posaconazole (p<0.0001), and terbinafine (p = 0.0428). The non-WT isolates for posaconazole were also significantly associated with the non-WT isolates for amphotericin B (p<0.0001) and terbinafine (p = 0.0005).

We did not observe reduced susceptibility to any of the tested antifungal drugs in 368 isolates (31.2%). We observed single-drug reduced susceptibility to amphotericin B in 60 isolates, to posaconazole in 41 isolates, to voriconazole in 9 isolates, and to terbinafine in 4 isolates. We also observed cross-reduced susceptibility in 8 isolates between amphotericin B and posaconazole, and 1 isolate demonstrated cross-reduced susceptibility between amphotericin B and voriconazole. For itraconazole, 491 isolates showed no reduced susceptibility pattern, whereas 687 isolates exhibited reduced susceptibility. We observed single-drug reduced susceptibility to itraconazole in 321 isolates. We identified co-reduced susceptibility with itraconazole in 270 isolates and observed multidrug reduced susceptibility to itraconazole in 96 isolates (Table 4).

Discussion

We phenotypically identified 1,178 feline S. schenckii complex isolates by fungal culture and determined them to have in vitro antifungal drug susceptibilities. Only 31.2% of all the isolates were susceptible to all the tested drugs. Terbinafine, voriconazole, amphotericin B, and posaconazole exhibited high efficacy, whereas itraconazole had limited efficacy. No association was apparent between the retroviral infections and non-WT isolates for amphotericin B, itraconazole, posaconazole, voriconazole, and terbinafine. Various patterns of in vitro antifungal drugs drug reduced susceptibility were characterized in this study, including single-drug reduced, co-reduced, and multidrug reduced susceptibility.

Samples were obtained from client-owned cats taken to veterinary clinics and with suspected feline sporotrichosis. Specimens were collected by attending veterinarians for routine diagnostic procedures. During 2023–2025, the number of cats diagnosed with sporotrichosis in Thailand increased steadily: 225 cases in 2023, increasing to 383 cases in 2024 and 570 cases in 2025. Reported cases represent laboratory-confirmed infections. Not all infected cats might have undergone confirmatory testing. As a result, the number of cases reported in this study likely underestimates the true number of feline sporotrichosis infections in Thailand. Although samples were submitted from multiple veterinary clinics across the country, geographic distribution was not analyzed in this study. Further epidemiologic studies are warranted to better define the incidence and prevalence of feline sporotrichosis in Thailand.

In this study, most of the cats were young adult, male, and domestic shorthair cats that were seronegative for FeLV and FIV. Those findings align with previously reported cases of 38 cats with sporotrichosis in Thailand during 2020–2022 (6). Young adult male cats exhibit roaming behaviors, which increases their exposure to pathogens. No specific breed has shown a predisposition for S. schenckii complex, and all cat breeds can be infected with this pathogen (6). The predominance of domestic shorthair cats likely reflects their high ownership in Thailand (23). Although retrovirus infections impair immune function by reducing the CD4+/CD8+ lymphocyte ratio (24), we found no association between the isolates from cats with seropositive retrovirus and those with non-WT phenotypes. The occurrence of non-WT S. schenckii complex isolates might be associated with virulent strains or prior antifungal drug exposure, rather than the underlying immune status of the host.

We used the CLSI M38-A3 BMD method as the reference standard for the surveillance of drug susceptibility in Sporothrix spp.; however, its complexity and the need for microbiological expertise limit its use in routine clinical settings. Commercially available antifungal drugs susceptibility testing platforms have limitations. The Vitek 2 (bioMérieux, https://www.biomerieux.com) automated system is widely used for antifungal drug susceptibility testing of Candida spp. and Cryptococcus spp. (25). The Vitek 2 has limited applicability for Sporothrix spp. because of the dimorphic nature and slow growth kinetics of the species. Likewise, discordance between Sensititer YeastOne (Thermo Fisher Scientific, https://www.thermofisher.com) and the CLSI reference method has been reported (26). The Sensititer YeastOne panel lacks key antifungal drugs, including terbinafine, which is the second-line treatment recommended drug for sporotrichosis (26,27). Using the CLSI M38-A reference method is essential for establishing an accurate baseline of antifungal drug susceptibility, particularly because of the increasing number of sporotrichosis cases in Thailand. The future development of user-friendly commercial antifungal drug susceptibility testing platforms for Sporothrix spp. would support the routine diagnosis and clinical management of sporotrichosis among physicians and veterinarians.

In this study, we applied established ECVs for S. schenckii complex to distinguish between the WT and non-WT MIC distributions for amphotericin B, itraconazole, posaconazole, and voriconazole (21). A study-specific cutoff at MIC97.5 was used to characterize the susceptibility profile of the feline S. schenckii complex isolates from Thailand to terbinafine. Most of the testing isolates were obtained from clinical cases that were unresponsive to prior antifungal drug therapy or were specifically submitted for MIC testing to guide veterinarians’ clinical decision-making. The high MIC values observed might reflect a subset of reduced susceptibility or clinically challenging strains rather than the baseline susceptibility of feline S. schenckii complex isolates from Thailand.

Itraconazole demonstrated a remarkably reduced efficacy compared with previous data from an earlier outbreak in Thailand (6,8). In this study, most of the isolates were classified as non-WT to itraconazole by MIC50 and exhibited reduced susceptibility (MIC90 >32 μg/mL), which contrasts with previous findings in which most of the isolates were WT with MIC50 at 0.5 μg/mL and non-WT with MIC90 at 4 μg/mL (6). The reduced susceptibility to itraconazole phenotypes we observed were reflected in the 16-fold increase in MIC50 and >8-fold increase in MIC90; a >4-fold increase in these values is indicative of acquired reduced susceptibility in non-WT strains (12,28,29). Our findings align with previously reported MICs from feline and human isolates from Thailand that exhibited reduced susceptibility to itraconazole and identified non-WT isolates (7,10,18). Furthermore, among the itraconazole non-WT isolates, a high rate (31.1%) of cross-reduced susceptibility and multidrug reduced susceptibility was detected, with prominent reduced susceptibility to itraconazole/posaconazole and itraconazole/amphotericin B and the multidrug combination of itraconazole, posaconazole, and amphotericin B. Cross-reduced susceptibility between itraconazole and posaconazole is often documented because both azole drugs share a common molecular target and overlapping binding sites within the ergosterol biosynthesis pathway (12). Moreover, the widespread use of itraconazole in feline sporotrichosis in Thailand often involves prolonged or inconsistent dosing because of multiple factors, including drug cost, bioavailability, owner compliance, difficulties in administering medication to cats, zoonotic concerns, and adverse effects. antifungal drugs treatment is not subsidized, and financial constraints might affect treatment continuity. In addition, limited access to veterinary care for stray cats and the absence of structured control programs might contribute to ongoing transmission. Those challenges can lead to treatment interruption or incomplete therapy, which might promote reduced susceptibility and multidrug resistance (12,30–33).

A reduction in susceptibility to amphotericin B is a concern we identified: MIC50 had shifted 8-fold (from 0.5 to 4 μg/mL) compared with previous data, in which non-WT strains were not detected (6). Amphotericin B is reserved for second-line therapy in severe disseminated sporotrichosis or in cases refractory to itraconazole (31,34). Most of the clinically challenging isolates in our study remained WT, with borderline susceptibility to amphotericin B. The use of amphotericin B as an empirical choice in those cases without prior antifungal drugs susceptibility testing would therefore have been precarious, because amphotericin B requires a minimum effective concentration of 4–8 µg/mL, which might risk dose-dependent nephrotoxicity (35).

Terbinafine is another second-line drug therapy used as a single treatment or in combination with itraconazole. Successful treatment with terbinafine remains controversial; some successful reports have been published in human and dog sporotrichosis cases, whereas the reported success rate in feline sporotrichosis caused by S. brasiliensis is low (36–38). In Thailand, this drug has been used frequently in cats when S. schenckii has failed to respond to itraconazole, and terbinafine has previously shown low MICs among S. schenckii isolates from Thailand and Malaysia that share closely related genotypes (6,7,27). In our study, terbinafine was the most potent agent in vitro, with consistently low MICs (1.3-fold increase in MIC50 and no change in MIC90) compared with those in previous reports (6). Cross-drug and multidrug reduced susceptibility to terbinafine, itraconazole, and other drugs were extremely low, especially among the non-WT isolates in our study. Our findings align with those of previous studies suggesting the use of terbinafine as an alternative drug for treating sporotrichosis against itraconazole non-WT isolates, either as a monotherapy or combined with posaconazole, on the basis of in vitro antifungal drug susceptibility testing and an in vivo Galleria mellonella model of S. schenckii infection (18).

This study had a very large and diverse collection of isolates from Thailand for in vitro susceptibility testing. Despite the clinically challenging nature of those isolates, terbinafine MICs remained stable and less variable than those of the other drugs, which indicated that the feline S. schenckii complex isolates from Thailand had a suitable susceptibility profile to terbinafine. We found diverse distributions of terbinafine MICs in the populations of S. schenckii complex native feline non-genotyped isolates from Thailand. In comparing our mode terbinafine value (mode MIC = 1 μg/mL) to that of a large, diverse population study (mode MIC = 0.5 μg/mL) (21), the difference was only 2-fold and not significant for susceptibility testing. Because of the increasing need for terbinafine to treat feline sporotrichosis and the rising rate of zoonotic infections in Thailand, we proposed a study-specific cutoff of 4 µg/mL for terbinafine for S. schenckii species complex. That cutoff might help monitor reduced susceptibility and support effective antifungal drug use, particularly because of the reduced susceptibility to itraconazole among strains in Thailand. Furthermore, including strains from Thailand in MIC datasets for ECV determination would broaden global studies on the susceptibility profiles of zoonotic S. schenckii.

The first limitation of this study is lack of correlation between the MICs and clinical treatment outcomes and the absence of disease severity analysis for non-WT isolates. Second, molecular identification was not performed to confirm species within the S. schenckii complex. Therefore, interpretation of MIC values based on ECVs for S. schenckii should be approached with caution. Feline sporotrichosis in Thailand is predominantly caused by S. schenckii s.s., supporting the use of those ECVs as a reference in this study (6–8), though species-level identification remains limited. A recent study proposed updated ECVs for Sporothrix species, which have been approved by the CLSI subcommittee and are expected in a future supplement (A.R. dos Santos, et al. unpub. data, https://www.biorxiv.org/content/10.64898/2025.12.19.695392v1). Those developments emphasize the necessity of species-level identification and standardized criteria for antifungal drug susceptibility testing and the need for standardized protocols to ensure consistent interpretation across studies. Future studies incorporating molecular identification are warranted to validate species-level distribution and improve the accuracy of antifungal drugs susceptibility interpretation. We primarily provided descriptive and surveillance data on in vitro antifungal drug susceptibility patterns and evidence of cross-reduced susceptibility. However, treatment outcomes cannot yet be reliably predicted from susceptibility profiles.

In conclusion, we found an increasing number of confirmed feline sporotrichosis cases in Thailand, with 1,178 cases reported within a 3-year period, together with the occurrence of reduced itraconazole susceptibility. Those results suggest that reliance on empirical therapy alone might be insufficient in refractory cases, as reduced susceptibility patterns can vary across regions and over time. In vitro drug susceptibility testing should be performed for disease surveillance and in selected complex cases.

Dr. Yurayart is a veterinarian and academic who is currently a faculty member at the Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand. She specializes in veterinary microbiology and mycology.

Top

Acknowledgment

We gratefully thank the veterinarians who submitted samples for fungal culture and antifungal drug susceptibility testing.

Top

References

  1. Oliveira  MM, Almeida-Paes  R, Gutierrez-Galhardo  MC, Zancope-Oliveira  RM. Molecular identification of the Sporothrix schenckii complex. Rev Iberoam Micol. 2014;31:2–6. DOIPubMedGoogle Scholar
  2. Chakrabarti  A, Bonifaz  A, Gutierrez-Galhardo  MC, Mochizuki  T, Li  S. Global epidemiology of sporotrichosis. Med Mycol. 2015;53:3–14. DOIPubMedGoogle Scholar
  3. Etchecopaz  A, Toscanini  MA, Gisbert  A, Mas  J, Scarpa  M, Iovannitti  CA, et al. Sporothrix brasiliensis: a review of an emerging South American fungal pathogen, its related disease, presentation and spread in Argentina. J Fungi (Basel). 2021;7:170. DOIPubMedGoogle Scholar
  4. Cheng  S, Zheng  S, Zhong  M, Gyawali  KR, Pan  W, Xu  M, et al. Current situation of sporotrichosis in China. Future Microbiol. 2024;19:1097–106. DOIPubMedGoogle Scholar
  5. Rudramurthy  SM, Shankarnarayan  SA, Hemashetter  BM, Verma  S, Chauhan  S, Nath  R, et al. Phenotypic and molecular characterisation of Sporothrix globosa of diverse origin from India. Braz J Microbiol. 2021;52:91–100. DOIPubMedGoogle Scholar
  6. Yingchanakiat  K, Limsivilai  O, Sunpongsri  S, Niyomtham  W, Lugsomya  K, Yurayart  C. Phenotypic and genotypic characterization and antifungal susceptibility of Sporothrix schenckii sensu stricto isolated from a feline sporotrichosis outbreak in Bangkok, Thailand. J Fungi (Basel). 2023;9:590. DOIPubMedGoogle Scholar
  7. Langsiri  N, Banlunara  W, Klaychontee  O, Worasilchai  N, Cognialli  R, Queiroz-Telles  F, et al. Targeted long-read sequencing analysis and antifungal susceptibility profiles of Sporothrix schenckii isolates from Thailand. PLoS Negl Trop Dis. 2025;19:e0013253. DOIPubMedGoogle Scholar
  8. Indoung  S, Chanchayanon  B, Chaisut  M, Buapeth  KO, Morteh  R, Jantrakajorn  S. Feline sporotrichosis caused by Sporothrix schenckii sensu stricto in Southern Thailand: phenotypic characterization, molecular identification, and antifungal susceptibility. Med Mycol. 2022;60:myac075. DOIPubMedGoogle Scholar
  9. Gremião  ID, Miranda  LH, Reis  EG, Rodrigues  AM, Pereira  SA. Zoonotic epidemic of sporotrichosis: cat to human transmission. PLoS Pathog. 2017;13:e1006077. DOIPubMedGoogle Scholar
  10. Jirawattanadon  P, Bunyaratavej  S, Leeyaphan  C, Chongtrakool  P, Sitthinamsuwan  P, Panjapakkul  W, et al. Clinical manifestations, antifungal drug susceptibility, and treatment outcomes for emerging zoonotic cutaneous sporotrichosis, Thailand. Emerg Infect Dis. 2024;30:2583–92. DOIPubMedGoogle Scholar
  11. Bernardes-Engemann  AR, Tomki  GF, Rabello  VBS, Almeida-Silva  F, Freitas  DFS, Gutierrez-Galhardo  MC, et al. Sporotrichosis caused by non-wild type Sporothrix brasiliensis strains. Front Cell Infect Microbiol. 2022;12:893501. DOIPubMedGoogle Scholar
  12. Waller  SB, Dalla Lana  DF, Quatrin  PM, Ferreira  MRA, Fuentefria  AM, Mezzari  A. Antifungal resistance on Sporothrix species: an overview. Braz J Microbiol. 2021;52:73–80. DOIPubMedGoogle Scholar
  13. Gremião  IDF, Miranda  LHM, Pereira-Oliveira  GR, Menezes  RC, Machado  ACS, Rodrigues  AM, et al. Advances and challenges in the management of feline sporotrichosis. Rev Iberoam Micol. 2022;39:61–7. DOIPubMedGoogle Scholar
  14. Gremião  IDF, Martins da Silva da Rocha E, Montenegro H, Carneiro AJB, Xavier MO, de Farias MR, et al. Guideline for the management of feline sporotrichosis caused by Sporothrix brasiliensis and literature revision. Braz J Microbiol. 2021;52:107–24. DOIPubMedGoogle Scholar
  15. Nakasu  CCT, Waller  SB, Ripoll  MK, Ferreira  MRA, Conceição  FR, Gomes  ADR, et al. Feline sporotrichosis: a case series of itraconazole-resistant Sporothrix brasiliensis infection. Braz J Microbiol. 2021;52:163–71. DOIPubMedGoogle Scholar
  16. Larsson  CE. Sporotrichosis and cryptococcosis. Presented at: World Small Animal Veterinary Association Congress; Mexico City, Mexico; 2005 May 11–14.
  17. Easterwood  LF, Harkin  KR, Rankin  AJ. Oral voriconazole therapy in cats with histoplasmosis yielded mild side effects and a favorable outcome. J Am Vet Med Assoc. 2023;261:1–5. DOIPubMedGoogle Scholar
  18. Aroonvuthiphong  V, Bangphoomi  N. Therapeutic alternatives for sporotrichosis induced by wild-type and non-wild-type Sporothrix schenckii through in vitro and in vivo assessment of enilconazole, isavuconazole, posaconazole, and terbinafine. Sci Rep. 2025;15:3230. DOIPubMedGoogle Scholar
  19. Indira  G. In vitro Antifungal susceptibility testing of 5 antifungal agents against dermatophytic species by CLSI (M38-A) micro dilution method. Clin Microbiol. 2014;3:1–5. DOIGoogle Scholar
  20. Clinical and Laboratory Standards Institute. Reference method for broth dilution antifungal susceptibility testing of filamentous fungi, 3rd ed. M38. Wayne (PA): The Institute; 2017.
  21. Espinel-Ingroff  A, Abreu  DPB, Almeida-Paes  R, Brilhante  RSN, Chakrabarti  A, Chowdhary  A, et al. Multicenter, international study of MIC/MEC Distributions for definition of epidemiological cutoff values for Sporothrix species identified by molecular methods. Antimicrob Agents Chemother. 2017;61:e01057–17. DOIPubMedGoogle Scholar
  22. Clinical and Laboratory Standards Institute. Principles and procedures for the development of epidemiological cutoff values for antifungal susceptibility testing. Wayne (PA): The Institute; 2016.
  23. Inpankaew  T, Sattasathuchana  P, Kengradomkij  C, Thengchaisri  N. Prevalence of toxoplasmosis in semi-domesticated and pet cats within and around Bangkok, Thailand. BMC Vet Res. 2021;17:252. DOIPubMedGoogle Scholar
  24. Hoffmann-Fezer  G, Mortelbauer  W, Hartmann  K, Mysliwietz  J, Thefeld  S, Beer  B, et al. Comparison of T-cell subpopulations in cats naturally infected with feline leukaemia virus or feline immunodeficiency virus. Res Vet Sci. 1996;61:222–6. DOIPubMedGoogle Scholar
  25. Zhang  M, Zhou  Z, Wang  D, Zhou  A, Song  G, Chen  X, et al. Comparative evaluation of Sensititre YeastOne and VITEK 2 against the clinical and laboratory standards institute M27-E4 reference broth microdilution method for the antifungal susceptibility testing of Cryptococcus neoformans and Cryptococcus gattii. Med Mycol. 2022;60:myac009. DOIPubMedGoogle Scholar
  26. Alvarado-Ramírez  E, Torres-Rodríguez  JM. In vitro susceptibility of Sporothrix schenckii to six antifungal agents determined using three different methods. Antimicrob Agents Chemother. 2007;51:2420–3. DOIPubMedGoogle Scholar
  27. Tan  XT, Ginsapu  SJ. Amran Fb, Sukur SbM, Shukor Sb. Susceptibility of filamentous fungi to voriconazole in Malaysia tested by Sensititre YeastOne and CLSI mirocilution methods. Research Square. 2021;.DOIGoogle Scholar
  28. Pfaller  MA, Diekema  DJ. Progress in antifungal susceptibility testing of Candida spp. by use of clinical and laboratory standards institute broth microdilution methods, 2010 to 2012. J Clin Microbiol. 2012;50:2846–56. DOIPubMedGoogle Scholar
  29. Espinel-Ingroff  A, Cuenca-Estrella  M, Fothergill  A, Fuller  J, Ghannoum  M, Johnson  E, et al. Wild-type MIC distributions and epidemiological cutoff values for amphotericin B and Aspergillus spp. for the CLSI broth microdilution method (M38-A2 document). Antimicrob Agents Chemother. 2011;55:5150–4. DOIPubMedGoogle Scholar
  30. Mawby  DI, Whittemore  JC, Fowler  LE, Papich  MG. Comparison of absorption characteristics of oral reference and compounded itraconazole formulations in healthy cats. J Am Vet Med Assoc. 2018;252:195–200. DOIPubMedGoogle Scholar
  31. Lloret  A, Hartmann  K, Pennisi  MG, Ferrer  L, Addie  D, Belák  S, et al. Sporotrichosis in cats: ABCD guidelines on prevention and management. J Feline Med Surg. 2013;15:619–23. DOIPubMedGoogle Scholar
  32. Kelly  SL, Lamb  DC, Kelly  DE, Manning  NJ, Loeffler  J, Hebart  H, et al. Resistance to fluconazole and cross-resistance to amphotericin B in Candida albicans from AIDS patients caused by defective sterol delta5,6-desaturation. FEBS Lett. 1997;400:80–2. DOIPubMedGoogle Scholar
  33. Vazquez  JA, Arganoza  MT, Boikov  D, Yoon  S, Sobel  JD, Akins  RA. Stable phenotypic resistance of Candida species to amphotericin B conferred by preexposure to subinhibitory levels of azoles. J Clin Microbiol. 1998;36:2690–5. DOIPubMedGoogle Scholar
  34. Kauffman  CA, Bustamante  B, Chapman  SW, Pappas  PG; Infectious Diseases Society of America. Clinical practice guidelines for the management of sporotrichosis: 2007 update by the Infectious Diseases Society of America. Clin Infect Dis. 2007;45:1255–65. DOIPubMedGoogle Scholar
  35. Gremião  I, Schubach  T, Pereira  S, Rodrigues  A, Honse  C, Barros  M. Treatment of refractory feline sporotrichosis with a combination of intralesional amphotericin B and oral itraconazole. Aust Vet J. 2011;89:346–51. DOIPubMedGoogle Scholar
  36. Francesconi  G, Francesconi do Valle  AC, Passos  SL, de Lima Barros  MB, de Almeida Paes  R, Curi  AL, et al. Comparative study of 250 mg/day terbinafine and 100 mg/day itraconazole for the treatment of cutaneous sporotrichosis. Mycopathologia. 2011;171:349–54. DOIPubMedGoogle Scholar
  37. Viana  PG, Figueiredo  ABF, Gremião  IDF, de Miranda  LHM, da Silva Antonio  IM, Boechat  JS, et al. Successful treatment of canine sporotrichosis with terbinafine: case reports and literature review. Mycopathologia. 2018;183:471–8. DOIPubMedGoogle Scholar
  38. Viana  PG, Gremião  IDF, da Silva Antonio  IM, Figueiredo  ABF, Correa  ML, Boechat  JS, et al. Is terbinafine an effective treatment for feline sporotrichosis? Vet Rec. 2024;195:e4435. DOIPubMedGoogle Scholar

Top

Tables

Top

Suggested citation for this article: Yurayart C, Yingchanakiat K, Thongbai A, Limsivilai O, Assawarachan SN, Jaroensong T, et al. In vitro antifungal drug susceptibility of feline Sporothrix schenckii complex isolates, Thailand, 2023–2025. Emerg Infect Dis. 2026 Jun [date cited]. https://doi.org/10.3201/eid3206.260135

DOI: 10.3201/eid3206.260135

Original Publication Date: May 21, 2026

Table of Contents – Volume 32, Number 6—June 2026

EID Search Options
presentation_01 Advanced Article Search – Search articles by author and/or keyword.
presentation_01 Articles by Country Search – Search articles by the topic country.
presentation_01 Article Type Search – Search articles by article type and issue.

Top

Comments

Please use the form below to submit correspondence to the authors or contact them at the following address:

Panpicha Sattasathuchana, Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand

Send To

10000 character(s) remaining.

Top

Page created: April 29, 2026
Page updated: May 21, 2026
Page reviewed: May 21, 2026
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
file_external